Like many gun parts, the AR-15 handguard is as personal a choice as stocks, sights or pistol grips and in direct proportion with owner’s wants and needs. While the aftermarket offer is overwhelmed with the plethora of them ranging from the battle-proven to the true featherweight AR-15 handguards even the names can be confusing as the rifle's forend is usually called the handguard, forearm or foregrip. Anyway, the AR-15 handguards are one part that's easy to change, and it is also one of the most-changed parts on the rifle, and for most of the novices adding an aftermarket, the forearm is the first step in personalizing their AR-15 rifle. While the primary role of a handguard is to protect shooters support hand from the heat of the barrel while firing, the AR15`s sleek and stylish appearance, the AR15 standard plastic handguards are bulky and clumsy making the rest of the AR look interrupted and incomplete.
There are hundreds of different versions which can improve rifle's comfort, versatility, or even enhance its accuracy potential. As for the classification, the AR-15 Handguard can be determined by the length of the piston or operation rod systems on an AR15 rifle, so we have three standard handguard lengths which match to gas systems with the same names: rifle, mid-length, and carbine gas systems. Also, there is the newest and shortest pistol gas system usually found on AR-15 style pistols. Moreover, the AR15 forends could be classified by its way of installation on a classic drop in (non-free-float design) and free-floating handguards which in turn allows further customization by defining the functionality and appearance of your rifle. Furthermore, both categories are subdivided on the rail, and the non-railed handguards and finally, as the cherry on the cake, all of these types could be made either of all metal construction, or carbon fiber reinforced polymers.
If we choose a railed handguard that means the rifle will utilize some combinations of Picatinny rail, (known as a MIL-STD-1913 rail), Keymod or M-LOK mounting rails. That forends usually have from one to four attachment points at three, six, nine and twelve o’clock positions and the most common type are the quad-rails, featuring the four rails that generally run the length of the handguard, enabling mounting of all different kinds of AR accessories such as lights, Harris bipods or vertical grips.
The other principal category consists of free-floating handguards intended to provide better precision and can be seen on match-grade rifles that value accuracy above all else. The free-floating handguard is mounted directly to the upper receiver without making any contacts with a barrel, allowing it to "float" and transfers better harmonics, resulting in slightly better accuracy. Similar to the previous category, there are free floating railed handguards as the most popular type of free-floating forehands. These are followed by the non-railed handguards or better known as "free float tubes" while the free float rails are available in many different lengths and configurations the most popular is standard quad rail handguard - named for its 4-Picatinny rails. Aside from its versatility, free float rails tend to be somewhat cumbersome, and since they require significant machine work, they are the most expensive of the handguard types. Unlike universal popularity of free float rails, the non-railed handguards belong to the somewhat specialized niche of rifles preferred by many competition shooters because free float tubes do not affect barrel harmonics and accuracy does not suffer.